Method of reducing metals.



R. J. McNITT.

METHOD OF REDUCING METALS.

APPLICATION FILED JAN. 2. 1913.

Patented Sept. 5, 1916.

wmma INVENTOR.

WITNESSES W Lr I? 017W t1 ti ROBERT J. MGNITT, OF PERTH AIVIBOY, NEWJERSEY, ASSIGNOR TO THE ROESSLER, & HASSLACHER CHEMICAL (30., OF NEWYORK, Y., A CORPORATION OF NEW YORK.

Mn'rnon or REDUCING METALS.

mower.

Application filed January 2, 1913.

To all whom it may concern Be it known that 1, ROBERT J. MoNrr'r, acitizen of the United States of America, residing at Perth Amboy,Middlese-x county, New Jersey, have invented a certain new and usefulMethod of Reducing Metals, of which the following is aspecification.

My invention relates to a new and useful method of reducing metals fromcompounds containing the same and it refers particularly to thereduction of metals from their compounds by electrolyzing the same underpressure.

The reduction of metals by electrolysis has been long practised by manyprocesses, but in all cases the electrolysis has been carried on underpressures substantially equal to the atmospheric pressure. Now I havefound that by carrying on the electrolysis under greater pressures thanatmospheric pressure, the reduction is more complete and results in moreeconomical separation.

Furthermore, whereas it has been found impossible to continuously and.economically reduce many metals by electrolysis by the processes andapparatus heretofore proposed. l have found that by the practice of myinvention this may be most satisfactorily accomplished.

I By way of illustrating my invention, I may cite as an example, thereduction of metallic sodium from molten sodium chlorid by electrolysisunder pressure. Among those familiar with this art it is considered tobe impossible to separate metallic sodium from molten sodium chlorid attemperatures in the neighborhood of the melting point of this compoundwhich is in the vicinity of the boiling point of sodium, so that thehigh volatility of the sodium metal at the former temperature gives,rise to various difiicillties. I find however that by carrying onelectrolysis under a pressure of 900 mm. mercury, while maintaining thetemperature of the electrolyte below its boiling point at atmosphericpressure, the boiling point of the liberated metal is raisedapproximately 100 C. and thelatter may be easily collected. i

I shall-explain my invention in connection with the accompanyingdrawing, which is a vertical longitudinal section showing in rather adiagrammatic way one form of elec trical apparatus suitable for thepurpose.

A indicates an anode of graphite or other Specification of LettersPatent.

I Patented Sept. 5, 1916..

Serial No. 739,710.

suitable material which is electrically connected with conductors Bextending through the external walls of the furnace. A cathode C, of anysuitable material, is shown as connected on its lower side with aconductor D extending through the bottom of the furnace. The walls ofthe furnace are shown as formed of steel-plates E lined on the insidewith a thin layer of asbestos F and the remaining spacebetween saidwalls and the rear sides of the electrodes and above the anodes isfilled with a suitable material such as brickworlLG preferably fire claybrick. The working chamber of the furnace extends from the bottom X upto cover H.

Z indicates a bell of any suitable material, shown as somewhat larger inits lateral extension than cathode C.

K represents a diaphragm of perforated metal, extending downward fromthe lower rim of the bell Z and hanging between the anode and cathodesurfaces.

The lower rim of bell Z is shown as terminating a short distance fromthe upper edge of the cathode C.

Z indicates a tube connected to the upper part of bell Z and passingthrough a cover H. Tube Z is connected by pipe L with pipe M, providedwith a valve M. A pipe N is shown as branching off from tube Z andconnecting to a vessel 0, provided with a Valve 0'. vessel 0 serving asa receiver.

A pipe P, provided with a valve P, conducts away the gases generated inthe process and another pipe Q, of suitable diameter and provided with asuitable cover, serves for charging the metallic compound, as forinstance sodium chlorid, into the furnace. A pressure gage R, carried bythe cover H, serves for indicating the pressure exerted on the contentsof the furnace.

lln carrying out my method of reducing metals from their compounds byelectrolyzing the same under pressure I prefer to charge the apparatus,described above, with molten sodium chlorid until it approximatelyreaches somewhat below branchpipe N so that the lower .ends of bothpipes M and Q are submerged somewhat in the liquid electrolyte.Immediately after charging in the molten sodium-chlorid I open valve Mand admit some inert gas, such as producer gas, through pipes M and L insuch quantities as to exert pressure on the electrolyte within theworking chamber and I then pass the electric current through the furnaceto start the electrolysis for the reduction of the sodium metal at thecathode C, Valve P is then opened just enough to throttle the escapingchlorin gas thus maintaining the pressure exerted on the electrolyte. Itis obvious that the chlorin will pass freely through the electrolyte andout through pipe P and valve P, whereas the path of the sodium, afterbeing separated at the cathode, is so directed that the sodium rises andis collected within bell Z. As the continuous electrolysis constantlyincreases the volume of the metallic sodium within the bell, owing tothe difi'erence in the specific gravity of the respective liquids, thesodium rises in the bell and finally overflows through pipe N intoreceiver 0.

It is obvious many changes may be made in the process described abovewithout departing from the spirit of my invention; one such change, forinstance, consists in carrying on the electrolysis under the hydrostaticpressure due to a high column of fluid which may consist in part orwhole of the molten electrolytic compounds, instead of creating thepressure by means of gases. Such change constitutes only oneillustrative modification of the method described and comes within thescope of my invention, inasmuch as it does not bring about a change ofmaterial conditions in regard to the chemical or physical sides of theinvention. It is further obvious that many other changes may be made, asfor instance charging the metallic compound in a solid instead of in amolten state; modifying the form and construction of the bell Z as toallow the introduction of cathode C and its conductor D from the topinstead of through the bottom or making other changes in the relativeposition of the electrodes without in the least interfering with theworking of the process as described.

The application of gas for exerting pressure on the electrolyte makes itessential that the gas fulfil certain conditions; first of all any gasused as an auxiliary should be reasonably dry; it is desirablefurthermore that it be inert as well to the chlorin gas as to the metalseparated at the cathode.

I Wish also to state that the electric furnace may be built in eithersquare or round shape and that the various material parts as forinstance the electrodes, may most readily be adapted to fit eithershape.The apparatus described is one of the forms which is well suited for thereduction of metallic sodium from its compounds, preferably sodiumchlorid, said reduction of metallic sodium being heredescribed simply asan example of my method of reducing metals.

The apparatus is'not claimed in connection with this application, as Ireserve the same as the subject-matter of another application for patentto be hereafter filed.

What I claim and desire to secure by Letters Patent is: l. A method ofreducing metallic compounds to their metals by electrolysis consistingin raising the boiling point of said metals by pressure on the moltenelectrolyte while maintaining the temperature of the electrolyte belowits boiling point at atmospheric pressure.

2. A method of reducing metallic compounds to their metals byelectrolysis consisting in raising the boiling point of said metals bypressure of a compressed gas on the molten electrolyte while maintainingthe temperature of the electrolyte below its boil ing point atatmospheric pressure.

3. A method of reducing metallic compounds to their metals byelectrolysis consisting in applying pressure to the metallic compoundsforming the electrolyte, by means of compressed inert gas and thenelectrolyzing the metallic compounds while under pressure.

i. A method of reducing metallic compounds to their metals byelectrolysis consisting in raising the boiling point of said metals bypressure of a gas generated by and compressed during the reductionprocess, on the molten electrolyte while maintaining the temperature ofthe electrolyte below its boiling point at atmospheric pressure.

5. A method of reducing metallic compounds to their metals byelectrolysis con sisting in exerting pressure on the metallic compoundsforming the electrolyte, by means of both a compressed inert gasadmitted to the furnace and a gas generated by and compressed duringthereduction process and then electrolyzing the metallic compounds whileunder pressure.

6. A method of reducing metallic compounds to their metals byelectrolysis consisting in providing in an electrolytic chamber saidmetallic compounds in a fluid state, applying pressure to the metalliccompounds by means of compressed gas, passing the electric currentthrough the bath of metallic compounds, separating the productsgenerated at the electrodes as desired and controlling the appliedpressure by means of gases liberated by the process and gases admittedfrom without.

7. A method of reducing metallic sodium from its compounds byelectrolysis consisting in raising the boiling point of the sodium bypressure on the molten electrolyte while maintaining the ten'iperatureof the electrolyte below its boiling point at atmospheric pressure.

8. A method of reducing metallic sodium from its compounds byelectrolysis consisting in raising the boiling point of the someme? diumby pressure of a compressed gas on the molten electrolyte whilemaintaining the temperature of the electrolyte below its boiling pointat atmospheric pressure.

9. A method of reducing metallic sodium from its compounds byelectrolysis consist ing in applying pressure to the sodium compoundforming the electrolyte, by means of a compressed inert gas andelectrolyzing the sodium compound While under pressure.

10. A method of reducing metallic sodium from its compounds byelectrolysis consisting in raising the boiling point of the sodium bypressure of a gas generated by and compressed during the reductionprocess, on the molten electrolyte while maintaining the temperature ofthe electrolyte below its boiling point at atmospheric pressure.

11. A method of reducing metallic sodium from its compounds byelectrolysis consisting in exerting pressure on the sodium compoundforming the electrolyte, by means of both a compressed, inert gas and agas generated by and compressed during the reduction, and electrolyzingthe sodium compound while under pressure.

12. A method of reducing metallic so dium from its compounds byelectrolysis consisting in providing in an electrolytic chamber saidsodium compounds in a fluid state, applying pressure to the sodiumcompounds by means of compressed gas, passing the electric currentthrough the bath of the sodium compounds, separating the productsgenerated at the electrodes as desired and controlling the appliedpressure by means of gases liberated by the process and gases admittedfrom without.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

v v ROBERT J. MGNITT. Witnesses: I

HERBERT PHILIPP, OTTO K. ZWIN-GENBERGER.

